Schwarz



Nov. 10, 1964 R. scHwARz 3,156,266

GUIDE MEANS FOR READING NEEDLES IN DOBBIES Filed Dec. 51, 1962 mum.

United States Patent O 3,156,266 GUIDE MEANS FOR READING NEEDLES IN DOBBIES Rudolf Schwarz, Horgen, Switzerland, assignor t Gebr. Stiiubli & Co., Zurich, Switzerland, a Swiss firm Filed Dec. 31, 1962, Ser. No. 248,786 Claims priori application Switzerland, Dec. 29, 1961, 1/62 1 Claim. (Cl. 139-68) This invention relates to dobbies and is more particularly concerned with the reading needles which act upon the pattern card to control the shafts of the loom.

In looms, the position of the shafts is controlled by the pattern on a pattern card which is read by reading needles and the position of the reading needles is transmitted to the shafts in order to position the shafts in corresponding relation. The reading needles scan the holes in the pattern card and either fall into a hole or rest upon the surface of the card, depending upon the pattern carried by the card. In order to avoid damage to the card, the reading needles fall on the card or into the holes in the card either by reason of their own weight or by the action of a light spring pressure. Because of the very small amount of force which is involved, it is important that the reading needles be freely movable. It is cus tomary to mount the needles perpendicularly. In order to promote easy movement of the reading needles and to minimize loss of the light force acting on them, one or more aligned perforated guide rails disposed above the pattern card serve as lateral guides for the needles. In order to reduce the friction between the sides of the needles and the walls of the perforations or holes in the guide rails, it is customary to lubricate the needles. However, in textile mills there is a fine dust or lint continuously present in the air and this lint tends to stick to the lubricant on the needles and to accumulate into a mass which hinders free movement of the needles in the guide rails. Furthermore, there is always the danger of corrosion in the holes of the guide rails, which also has an adverse action upon the movement of the needles, particularly if the accumulated lint problem is also present.

It is possible to replace the metal guide rails by perforated guide rails formed from a synthetic plastic material so that the need for lubrication can be eliminated. Such rails, however, have the disadvantage that they do not have good dimensional stability and their position tends to vary under the influence of ageing, dampness and temperature so that they do not provide the desired guiding action for the needles and they do not insure that the needles will always lie exactly over the pattern card holes, which is, of course, essential for proper operation. This is particularly the case when several guide rails are aligned in superposed relationship.

It is, accordingly, an object of the present invention to provide, in a dobby, guide rail means for the reading needles for the pattern card which are free from the drawbacks and disadvantages of the guide rail constructions discussed above and which insure smooth, friction-free guiding of the reading needles at all times without need for lubricating the needles themselves.

In accordance with the invention, there is provided a reading needle guide rail which is formed from a perforated metal core, viz. a body formed with a plurality of holes or apertures to receive the reading needles,'and a cover or coating formed from a synthetic plastic around the core, the cover not only overlying the body of the core but also overlying the walls of the apertures in the body.

3,156,266 Patented Nov. 10, 1964 The invention will now be described with respect to a specific embodiment thereof, taken in connection with the accompanying drawing, wherein FIG. 1 is a plan view of a guide rail embodying features of the present invention;

FIG. 2 is a cross-sectional view of the guide rail shown in FIG. 1, the section being taken at line 22 of FIG. 1 through one of the holes or apertures in the rail and showing a portion of a reading needle extending through the aperture; and

FIG. 3 is a fragmentary elevation view partly in section of a dobby provided with guide means according to the invention.

Referring to the drawing, the guide rail of the invention is composed of a metal core 1, suitably formed from a ferrous material such as iron or steel, which is provided with a plurality of apertures 3 and which is covered by a covering or coating of a synthetic plastic 2. As will be seen from FIG. 2, the plastic coating 2 not only overlies the body of the core 1 but also overlies the walls of the apertures 3. The entire body of the core is covered with the plastic coating 2 except for end portions 5 which are used for mounting the guide rail in a dobby, as shown in FIG. 3, either by itself or with other like guide rails, which are suitably disposed in superposed vertically spaced-apart relationship, in order to guide reading needles 4 perpendicularly in relation to a driven pattern card being sensed. It being understood that the needles are actuated by known dobby mechanism, not shown, for pattern card reading systems-to the positions illustrated in solid and broken lines. The manner of mounting the guide rail forms no part of the invention and it may be mounted in the dobby 7, shown fragmentarily, in any convenient manner, e.g. by means of clamps, or bolts, or the like. The synthetic plastic material which is used as the coating can be any plastic material which has a low coefiicient of friction, particularly with respect to metal, so that the metal reading needles will freely slide over its surface, and at the same time the plastic material should also be resistant to light blows. Particularly suitable synthetic plastic materials are polyamide, polyethylene, polystyrol or the product known as Teflon (a plastic comprising tetrafiuoroethylenepolymer) or polyvinylchloride. It will be understood, however, that the invention is not limited to this material and that other like or similar synthetic plastic materials may be employed.

The guide rail constructed in accordance with this invention insures optimum and true guiding of the reading needles at all times since it has dimensional stability by reason of the presence of the metal core, which re sists the adverse action which ageing, temperature and dampness have upon plastic materials, and the plastic cover or coating which protects the core against corrosion and insures free sliding movement of the reading needles without requiring supplemental lubrication.

It will be understood that various changes and modifications may be made in the embodiment herein described without departing from the scope of the invention as defined in the appended claim. It is intended, therefore, that all matter contained in the foregoing description and in the drawing shall be interpreted as illustrative only and not as limitative of the invention.

I claimi For use in a shed-forming machine having a perforated pattern reading.mechanismcomprising reciprocably 0p- 7 a a 3 erated reading needles for reading perforations, an improved guide rail comprising, ametal core having a plurality of spaced apertures to receive the reading needles for reciprocable travel therein, a low-friction cover of synthetic material on said core extending along the length 2 thereof including covering the inner surfaces of said apertures to provide low-friction cover comprising a material having a coefficient of friction sufliciently low to preclude the necessity of lubricating said'ncedles, said core comprising a ferrous metal and having-opposite ends extending'outwardly of said cover material, and said'cover material comprising a plastic.

References Cited by the Examiner UNITED STATES PATENTS Straubli 139-68 Wiget 139-68 Turner 13968 Carlson l3986 Reynolds 139-68 Bitzer 661l0 10 DONALD W. PARKER, Primary Examiner.

RUSSELL C.- MADER, Examiner. 

